Polyimides are useful as components which require excellent thermal, electrical and/or mechanical properties. For general discussion of polyimides preparation, characterization and applications see Polyimides, Synthesis, Characterization and Applications, K. L. Mittal, ed Plenum, N.Y. 1984.
Polyimides based on pyromellitic dianhydride and various organic diamines are disclosed in U.S. Pat. No. 4,485,140 to Gannett et al (E. I. DuPont de Nemours and Co.).
Polyimides based on diamines such as 2,2'-di-(p-aminophenyloxy)diphenyl and various dianhydrides are disclosed in U.S. Pat. No. 4,239,880 to Darms (Ciba-Geigy Corp.).
Harris et al. in U.S. patent application 07/315,327, has disclosed the preparation of soluble polyimides based on polyphenylated diamines. The polyimides taught in this reference are typically rod like polyimides and possess little if any thermoplastic properties.
In U.S. Pat. Nos. 4,271,288, 4,239,694 and 4,421,929, Woo (DOW Chemical Co.) teaches the use of certain tetracarboxylic acids as condensation monomers with diamines including oxyalkylene and alkyenedioxy diamines. Howewer, none of these diamines had geminal alkyl groups beta to the carbon atom bearing the aromatic amino end group.
Numerous patents deal with the manufacture of composites utilizing carbon fibers or other similar fibrous reinforcing agent with polyimides.
In U.S. Pat. No. 4,851,280, Gupta teaches the use of carbon fiber reinforced polyimide composites for fabricating tools. Gupta teaches the use of a different class of polyimides than those employed in the present invention.
In U.S. Pat. No. 4,395,514, Edelman teaches a process for the preparation of polyimide composites including carbon fiber reinforced polyimide composites. The main thrust of the Edelman patent is the use of a class of cyclic peroxyketal catalysts. Edelman teaches the use of divalent aryl radicals.
None of the above composite patents teach or insinuate that the diamines, polyimides or polyimide composites of the present invention would have the unusual properties of the above diamine, polyimides and polyimide composites.